Pigging Operation in Tanks with AIFR 1

[KVARM]

What will be the best solution to avoid floating roof (Pontoon type) damages when the pig goes inside the tank?

The pigging operations are done by using Foam pig or Cup pig pressurized with Nitrogen.


Can it be avoided by using full contact floating roof?

 

[IFRs]

The pig should never go into the tank - it should to into a pig catcher.
The piping outside the tank should have a branch, bars to guide the pig, a bypass line, pig catcher, instrumentation, etc.
The type of floating roof won't cure bad piping design or inattentive operations.
Then, if the pig does bypass the tank, your problem is potentially a massive amount of high pressure gas entering the tank and damaging the floating roof.
Again, the type of floating roof won't matter much, if at all.
Best option in my opinion is to design a mixed phase liquid/gas diffuser for the inlet pipe and possibly have gas relief vents on the floating roof above the diffuser.

 

[LittleInch]

Blowing a pig with gas into any tank other than open roof is a very bad idea.

I don't understand what you're trying to do?

Will the tank be empty with manholes open?

Is the roof going to be sitting on its legs (high position)
Why would the pig damage the pontoons?

Why is anyone actually trying to do this?
Who is authorising it (hopefully not you?)

Nothing here makes sense at the moment. Please elaborate.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[MJCronin]

Amen, LittleInch ...

This sounds like a crime/accident scene waiting to happen...

I agree with:

Why is anyone actually trying to do this?
Who is authorising it (hopefully not you?)

W O W !!!!

MJCronin
Sr. Process Engineer

 

[HTURKAK]

I looked to this post several times..still not sure i understand the thread . I assume that, the tank exposed to a pigging operation when it was empty with IFR landed position and pontoon type IFR was damaged.

If so, the following TROUBLESHOOTING could be adopted for the case....